为什么现在大家开发Angular应用都不用$scope改用this了?

Question

我想知道这样有什么优点吗?还是为了什么？

比如下面这段代码:

 function DemoCtrl ($timeout, $q, $log) {

    var self = this;

    self.simulateQuery = false;

    self.isDisabled    = false;

    // list of `state` value/display objects

    self.states        = loadAll();

    self.querySearch   = querySearch;

    self.selectedItemChange = selectedItemChange;

    self.searchTextChange   = searchTextChange;

    self.newState = newState;

}